1
1 mark
What happens when iodine is bubbled through aqueous potassium bromide?
Iodine is oxidised to iodide ions.
Potassium bromide is reduced to bromine.
Bromide ions are oxidised to bromine.
No reaction occurs.
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The Chemical Properties of the Halogen Elements & the Hydrogen Halides (Cambridge (CIE) AS Chemistry): Exam Questions
Exam code: 9701
47 mins14 questions
2
1 mark
What happens when chlorine gas is bubbled through aqueous potassium iodide?
Iodide ions are oxidised to iodine.
Chlorine is oxidised to chlorate (V) ions.
Chlorine is oxidised to chloride ions.
There is no observable reaction.
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3
1 mark
When halogen sodium salts react with concentrated sulfuric acid which of the halide ions, chloride, bromide or iodide, acts as a reducing agent?
1 | Cl– |
2 | Br– |
3 | I– |
1, 2 and 3
1 and 2
2 and 3
1 only
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1
1 mark
On being heated, hydrogen iodide breaks down more quickly than hydrogen chloride.
Which statements does not explain this faster rate?
The breakdown of HCl is more exothermic than that of HI
The reaction of the breakdown of HI has smaller activation energy than that of HCl
The HCl bond is stronger than the HI bond
The HI bond is longer than the HCl bond
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2
1 mark
On contact with a hot glass rod, which gaseous hydride most readily decomposes into its elements?
Ammonia
Steam
Hydrogen iodide
Hydrogen chloride
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3
1 mark
When a hot platinum wire is plunged into a test tube of hydrogen chloride, no change occurs. However, if the experiment is repeated with hydrogen iodide, the gas is decomposed into its elements.
Which factor does not result in this behaviour?
the strength of the hydrogen-halogen bond
the standard enthalpy of formation, ΔHfθ, of each of the products of decomposition
the electronegativity of the chlorine atom
the size of the halogen atom
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4
1 mark
The table below describes the observations made when aqueous silver nitrate is added to three different halide ions, followed by the addition of aqueous ammonia.
Which row correctly matches the halide ion with its precipitate colour and its solubility in ammonia?
Row | Halide ion | Colour of precipitate with AgNO3 (aq) | Observation on adding ammonia |
|---|---|---|---|
A | Cl- | White | Dissolves in dilute NH3 |
B | Br- | White | Dissolves in concentrated NH3 only |
C | I- | Cream | Remains insoluble in concentrated NH3 |
D | Br- | Cream | Dissolves in dilute NH3 |
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1
1 mark
X, Y and Z represent different halogens. The table shows the results of nine experiments in which aqueous solutions of X2, Y2 and Z2 were separately added to separate aqueous solutions containing X-, Y- and Z- ions.
| X- (aq) | Y- (aq) | Z- (aq) |
X2 (aq) Y2 (aq) Z2 (aq) | no reaction X2 formed X2 formed | no reaction no reaction no reaction | no reaction Z2 formed no reaction |
What is the correct order to show the decreasing strength of the ions X-, Y- and Z- as reducing agents?
X- > Y- > Z-
X- > Z- > Y-
Y- > Z- > X-
Z- > X- > Y-
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2
1 mark
A dark red/brown solution is formed when a halide salt containing the halide ion Y- reacts with aqueous chlorine. This solution then forms a violet solution when shaken with a cyclohexane solution.
What is halogen, Y?
Fluorine
Iodine
Iodide
Bromide
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3
1 mark
Which statement about Group 7 elements is not correct?
Fluorine is the weakest reducing agent in Group 7.
The bond dissociation energy of the hydrogen halides from HCl to HI increases.
CH3I would produce a silver halide precipitate with acidified AgNO3 faster than CH3Cl or CH3Br.
Astatine has a lower first ionisation energy than iodine.
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